Migration and clinical outcome of mobile-bearing versus fixed-bearing single-radius total knee arthroplasty: A randomized controlled trial

作者：Van Hamersveld Koen T^*; Marang Van De Mheen Perla J; Van Der Heide Huub J L; Van Der Linden Van Der Zwaag Henrica M J; Valstar Edward R; Nelissen Rob G H H

来源：Acta Orthopaedica, 2018, 89(2): 190-196.

DOI：10.1080/17453674.2018.1429108

Background and purpose Mobile-bearing total knee prostheses (TKPs) were developed in the 1970s in an attempt to increase function and improve implant longevity. However, modern fixed-bearing designs like the single-radius TKP may provide similar advantages. We compared tibial component migration measured with radiostereometric analysis (RSA) and clinical outcome of otherwise similarly designed cemented fixed-bearing and mobile-bearing single-radius TKPs.Patients and methods RSA measurements and clinical scores were assessed in 46 randomized patients at baseline, 6 months, 1 year, and annually thereafter up to 6 years postoperatively. A linear mixed-effects model was used to analyze the repeated measurements.Results Both groups showed comparable migration (p = 0.3), with a mean migration at 6-year follow-up of 0.90mm (95% CI 0.49-1.41) for the fixed-bearing group compared with 1.22mm (95% CI 0.75-1.80) for the mobile-bearing group. Clinical outcomes were similar between groups. 1 fixed-bearing knee was revised for aseptic loosening after 6 years and 2 knees (1 in each group) were revised for late infection. 2 knees (1 in each group) were suspected for loosening due to excessive migration. Another mobile-bearing knee was revised after an insert dislocation due to failure of the locking mechanism 6 weeks postoperatively, after which study inclusion was preliminary terminated.Interpretation Fixed-bearing and mobile-bearing single-radius TKPs showed similar migration. The latter may, however, expose patients to more complex surgical techniques and risks such as insert dislocations inherent to this rotating-platform design.

• 出版日期2018